If the node is visible to Anonymous Monk and people who refuse to see unapproved content

If the node will show up on the frontpage

At level 5 or higher (I guess) you start to see the "approval nodelet" that gives you the right (and responsibility) to decide if a post fits into these categories. Unapproved posts stay just that, unapproved. That means that they don't show up on the frontpage and that they aren't available to Anonymous Monk and people who chose not to see unapproved content. No other bad magic happens, but if a node dosen't get at least the "normal" approval, it will most likely gather a bad reputation anyway, because something is wrong if nobody considers a node worthy for the general public.